This invention relates to read-write heads used in magneto-optic and optical disk drives (e.g. CD read-only memories, CD read-write memories, and DVD media). This invention further relates to low cost high performance read-write heads.
Presently, magneto-optic and optical disk drives include a laser beam source which provides a laser beam that strikes the magneto-optic or optical disk. In the case of a magneto-optic disk, during writing operations, the laser beam and a magnetic field are simultaneously applied to the disk, and the presence of both the laser beam and magnetic field result in data being written to the disk.
In magneto-optic and optical disk drives, during read operations, a laser beam strikes the disk, and data is read by detecting light that reflects off the disk. In the case of a magneto-optic disk, depending upon the data recorded in the disk, the polarization of the laser light is altered by the magneto-optic layer within the disk. In the case of optical disks, different techniques can be used to record data in the disk. Some examples of optical and magneto-optic disks are discussed in European patent application EP 0 475 452 A2, incorporated herein by reference.
For both magneto-optic and optical disk drives, it is desirable to cause the laser beam to strike the disk at a very small spot to facilitate a high data recording density. It is an object of this invention to provide a structure which enables reading and/or writing data from or to a magneto-optic or optical disk which focuses a laser beam on a very small spot on the disk. It is also an object of this invention to provide such a structure in an inexpensive manner such that it can be mass-produced using wafer scale manufacturing techniques.